Electrons, because of their wave-particle duality, can be accelerated to have picometer wavelength and focused to image in real space. With the impressive advances made in transmission electron microscopy (TEM), STEM, and aberration-corrected TEM, it is now possible to image with high resolution, reaching the sub-Angstrom scale. Together with the progress made in electron crystallography, tomography, and single-particle imaging, today the electron microscope has become a central tool in many fields, from materials science to biology. For many microscopes, the electrons are generated either thermally by heating the cathode or by field emission, and as such the electron beam is made of random electron bursts with no control over the temporal behavior. In these microscopes, time resolution of milliseconds or longer, being limited by the video rate of the detector, can be achieved, while maintaining the high spatial resolution.
Despite the advances made in TEM techniques, there is a need in the art for improved methods and novel systems for ultrafast electron microscopy.